1. Field of the Invention
The present invention relates to a disk unit for driving an optical disk (e.g., CD-R/RW, DVD-R/-RW/RAM/+R/+RW) as a recording medium which stores a large amount of information in information systems such as various computer systems.
2. Description of the Prior Art
The disk unit incorporated for example in a personal computer is usually provided with a disk tray loaded with a disk, the disk tray being constructed so as to move forward and backward. The disk loaded on the disk tray is driven within a body of the disk unit to perform read or write of information.
On the other hand, as a disk unit not using such a disk tray, a slot-in type disk unit tends to be adopted more and more. The slot-in type disk unit is suitable for the reduction in thickness and size of personal computers. In the slot-in type disk unit, the disk tray is not used for load and unload of a disk with respect to the unit body, so when an operator inserts the greater part of the disk into a slot, a loading mechanism installed in the unit body operates and loads the disk automatically.
FIGS. 49 and 50 show the construction and operation modes of a loading mechanism in a conventional slot-in type disk unit. According to the illustrated construction, when an operator inserts a disk D into a slot, the disk D reaches its position shown in FIG. 49 while its height direction and right and left positions are restricted by a pin 100a provided at a tip of a first pivotable member 100 and also by right and left guide members 101, 102 and further restricted halfway by a pin 103a provided at a tip of a second pivotable member 103.
At this time, the pin 100a at the tip of the first pivotable member 100 is pushed by the disk D and the first pivotable member 100 rotates in the direction of arrow 100A. Likewise, the pin 103a at the tip of the second pivotable member 103 is pushed by the disk D and the second pivotable member 103 rotates in the direction of arrow 103A. Further, a switch lever 104 is pushed against an end portion of the second pivotable member 103 and rotates in the direction of arrow 104A, thereby actuating a detection switch 105.
Upon operation of the detection switch 105, drive means 106 starts operating and a first slide member 107 starts moving in the direction of arrow 107A. An end of the first slide member 107 and an end of a second slide member 108 are connected together through a slide connecting member 109 which is pivotably supported by a pin 110. Consequently, the second slide member 108 moves forward in the direction of arrow 108A in synchronism with retreat of the first slide member 107.
Once the first slide member 107 starts to retreat, a driven pin 100b of the first pivotable member 100 which is cantilevered by the first slide member 107 is guided by a cam groove 107a of the first slide member 107, so that the pivotable member 100 rotates in the direction of arrow 108B around a fulcrum 100c, whereby the pin 100a at the tip of the first pivotable member 100 conveys the disk D until abutment against pins 111a and 111b of a disk positioning member 111 in the direction of arrow 107A.
At this time, the pin 103a of the second pivotable member 103 rotates in the direction of arrow 103A and therefore moves in the arrow 103A direction in synchronism with the pin 100a provided at the tip of the first pivotable member 100 while supporting the disk D. Then, after abutment of the disk D against the pins 111a and 111b of the disk positioning member 111, the pin 103a rotates to a position spaced a little from the disk D.
The above is an operation mode of the loading mechanism in case of loading the disk D into the disk unit. The operation mode of the loading mechanism in case of unloading the disk D to the exterior of the disk unit is reverse to the above operation mode. More specifically, when the drive means 106 is turned ON in the opposite direction in accordance with an unloading command in a state in which the disk D is at a predetermined position in the interior of the disk unit as shown in FIG. 50, the first slide member 107 starts to move forward in the direction of arrow 107B and, in synchronism therewith, the second slider member 108 connected to the slide connecting member 109 starts to retreat in the direction of arrow 108B. Consequently, the first pivotable member 100 rotates in the direction of arrow 100A and the second pivotable member 103 rotates in the direction of arrow 103B, so that the disk D is unloaded to the exterior of the disk unit while being supported by the pins 100a and 103a provided respectively at the tips of those pivotable members.
The disk D loaded into the disk unit is clamped by a clamp head 112 which is adapted to move vertically at a predetermined position. The clamp head 112 is integral with a turntable 113 fixed to a drive shaft of a spindle motor 114. The spindle motor 114 is disposed on a frame member (not shown), which frame member is moved vertically by a lift mechanism (see, for example, Japanese Patent Laid-Open Publication No. 2002-117604).
In the disk unit configured as above, in order to effect a cooperative operation of both first pivotable member 100 and second pivotable member 103, the first slide member 107 and the second slide member 108 are connected with each other through the slide connecting member 109 so as to synchronize their forward and backward movements. Therefore, the positions in the course of conveyance of the pins 100a and 103a provided respectively at the tips of the first and second pivotable members 100, 103 must be determined on the basis of an outer periphery edge of a disk of a specific diameter.
Disks defined by the standard applied to such a disk unit as the above disk unit are generally called 12 cm disk and 8 cm disk, the former being the highest in versatility. Driving a disk of such a different diameter in a disk tray type disk unit can be done by only loading the disk to a corresponding groove formed in a disk tray. However, in the disk unit having such a mechanism as disclosed in Japanese Patent Laid-Open Publication No. 2002-117604, a pivoting range of the first pivotable member 100 and that of the second pivotable member 103 are designed in a corresponding relation to the conveyance of the 12 cm disk, so that the conveyance and hence drive of the 8 cm disk cannot be done at all.